body {
    font-family: system-ui, sans-serif;
  }
  
  * {
    box-sizing: border-box;
  }
  
  nav {
    padding: 20px;
  }
  
  .sidebar {
    padding: 10px;
    height: 500px;
    float: left;
    width: 30%;
  }
  
  .post {
    padding: 20px;
    float: left;
    width: 60%;
  }
  
  h1, h2 {
    padding: 0;
  }
  
  ul, li {
    margin: 0;
  }
  
  .post p {
    font-size: larger;
    font-family: Georgia, serif;
  }
  
  .comments {
    margin-top: 40px;
  }
  
  .comment {
    border: 2px solid #aaa;
    border-radius: 4px;
    padding: 20px;
  }
  
  /* https://codepen.io/mandelid/pen/vwKoe */
  .spinner {
    display: inline-block;
    transition: opacity linear 0.1s;
    width: 20px;
    height: 20px;
    border: 3px solid rgba(80, 80, 80, 0.5);
    border-radius: 50%;
    border-top-color: #fff;
    animation: spin 1s ease-in-out infinite;
    opacity: 0;
  }
  .spinner--active {
    opacity: 1;
  }
  
  @keyframes spin {
    to {
      transform: rotate(360deg);
    }
  }
  @keyframes spin {
    to {
      transform: rotate(360deg);
    }
  }